of more coagulant, it may be a fairly long period before he knows the cause.

It is known that there are a few instances where the addition of lime before the alum in a fairly hard water aids coagulation. The assumption is that part of the precipitate is calcium carbonate. In such cases more alumina usually remains in solution than would be the case if the pH of the water was about 6.0. It, of course, is not economical to adjust the pH to the optimum point, and the treatment as outlined by Mr. Fuertes is the proper one to use.

DISCUSSION

PROFESSOR BARTOW: Mr. Hawley asked me to discuss this paper. In the last sentence read by Mr. Brown, the paper states:

"The water falls directly into the mixing chambers, at which point it receives the coagulants, the dosage varying from 0.2 to 1.0 grains per gallon of alum and 0.0 to 0.5 grains per gallon of lime. Although the raw water has a bicarbonate alkalinity of 100 p.p.m. and over, it is found that a small dosage of hydrated lime improves the coagulation, contrary to the customary phenomena."

We have tried some experiments on Mississippi River water and find that the addition of lime does not help. The addition of sulphuric acid with the alum allows a much smaller dosage of alum to be used. I am told that with Missouri River water the addition of lime and iron sulphate allows a decrease in alum. We must not get from this paper the idea that the addition of lime to alum would be a help in all cases.

PRESIDENT HATTON: May I ask, Professor, how you measure the amount of sulphuric acid and alum required?

PROFESSOR BARTOW: In Mississippi River water it varies from time to time and the dosage of alum without lime is as high as 6 grains per gallon sometimes. The use of a small amount of sulphuric acid where they are using from 4 to 6 will cut it probably to two.

PRESIDENT HATTON: Do you measure it by the PH value? PROFESSOR BARTOW: Yes, sir.

MR. MCCALLUM: I don't notice anything in there where peat water is treated by liquid chlorine and other re-agents, say like chloramine. My experience with liquid chlorine used as a sterilizing agent was that it had very little effect on colored water until the cost of it became so great in comparison with chloramine, (mixture of lime and alum) that it practically equaled twice the cost of the other. That is before the water was clarified. In the purification that is mentioned there I suppose it means altogether where mechanical equipment is used, doesn't it? Or does it mean the purification of the water without clarification?

SECRETARY BROWN: This paragraph of "Aerators, Mixing Chambers and Coagulation Basin, I think perhaps that is what Professor Bartow made his selection from. "After passing through the five mixing chambers, having a total retention period of twenty minutes, and the coagulation basin, the water flows directly to the filters, having had a total coagulation period of one hour.' "***"The coagulated water enters each filter from a flume at the end away from the operating floor. All of the other filter connections are made to pipes and flumes in a pipe gallery under the operating floor.

"The filtering material is hard anthracite coal, effective size 0.6 to 0.8 mm. ; uniformity co-efficient 1.5, placed in beds five feet deep and supported by 14 inches of gravel, graded in three layers and of a size varying from .075 to 0.05 inches. The strainer system is of 3-inch perforated pipes, 8 inches cc. with 3" holes in their bottoms, 4 inches cc., the same pipes being arranged for a uniform distribution of both air and water wash. Reinforced concrete wash water gutters are used. Extremely sensitive inspection wells 7 feet deep are provided on the individual filter effluents. These have white glass bottoms which reflect light thrown from a high-powered incandescent lamp above. The wells have transparent plate glass covers; the filters operate under a maximum head loss of three feet. They are controlled by hand without rate controllers, the water always being under close observance. The filters have both air and water wash, the latter varied in rate according to the character of the water treated, the usual operating range being eight to fifteen inches per minute. All filters have rate of flow, loss of head, and rate of wash gauges. The latter are actuated by loss

The

of head of wash water and were calibrated in the field. dials will be checked at intervals of time and if necessary corrected. The filters are equipped with hydraulic valves, controiled from operating stands. The valves have attached directly to them position indicators, all visible from the operating stands. And so forth.

PRESIDENT HATTON: I presume, Dr. Bartow, the reason why sulphuric acid adds effectiveness in the Mississippi River water is that the Mississippi River water carries a high amount of insoluble solids, does it not, and the sulphuric acid increases intensity of the electric current over the alum. Would that be true?

PROFESSOR BARTOW: It might be. It might be the sulphuric acid adds the sulphate ion. It might be sulphate would serve as a catalyzer.

MR. SHRIMER: I would like to ask what this sulphate would amount to in the water.

PROFESSOR BARTOW: The Missouri River and Mississippi River would vary in sulphate content, varying with the dilution, and probably from 10 to 30 parts per million. It would be a rough estimate, however.

JUSTIFICATION OF A PROGRAM TO BEAUTIFY WATER

WORKS PROPERTY.

By Charles S. Denman, Superintendent of Water Works, Des Moines, Iowa

The value and the actual necessity for public parks is everywhere recognized and needs no argument. What better place then for a park than the grounds and stations used by the city for its water supply. No matter how unfavorable the location it is susceptible to improvement and can often in a most striking and effective manner arouse the pride and interest of the people in their water works, which is of such vital importance to the community by making it an attractive place of resort.

After all is not all of this also a matter of plain business common sense? Is it not on the same principle as a farmer who spends part of his time in planting trees and shrubbery and is raising a few flowers around his house? Yes! it pays to beautify a Water Plant. The capital expenditure and the cost of upkeep is justified. A city should not be a place primarily in which to do business but a place in which to live and to make it desirable-its institutions should be marks of beauty.

The plant and property of the Des Moines Water Company was acquired by purchase by the City of Des Moines in November 1919. In January 1920 the suction well which had served the City since 1882 suddenly failed and for a period of two weeks during the hours of heavy pumpage the higher portions of the City were without water. The Water Board proceeded, without delay, to construct a New Pumping Station on the south side of the Raccoon River. This construction and the abandonment of the old plant had been urgently recommended by the Company's Consulting Engineers several years previously. The danger at the old plant had been apparent for some time, but the construction of the new station had been deferred owing to negotiations, which had been pending for a number of years for the sale of the property to the City.

The site of the new pumping station is on ground subject to overflow from the river close to the business district, located on a main highway leading into country and suburban areas which are rapidly developing. The elevation of the ground was about 112 water works datum which was more than six feet below high water. The pumping station and grounds were designed to withstand floods which necessitated the grading and filling of the grounds and roadways, in the immediate vicinity, to an elevation of 120 or about an average of an eight foot fill. Deep borrow pits were dug and about 40,000 yards of earth, including that taken from the pump pits and suction well, were thus scooped up to bring the grounds and roadways to the desired elevation. To have hauled this yardage from a point outside the site would probably have cost about $60,000.00, but it was done at a cost of approximately 26 cents per yard or $14,400.00, a gross saving of approximately $45,600.00.

Landscape architects were employed to make a comprehensive plan for the beautification of the grounds. This plan called for the puddling, with gumbo one foot in depth, the large bor row pit 700 feet long and 100 feet wide located immediately in front of the station. The gumbo was obtained at a nearby point adjacent to the river at a cost of $1,478.00, thus the unsightly hole in front of the plant was converted into a beautiful lagoon. To add to the effect, the banks were trimmed, sloped and planted with shubbery, consisting principally of sumachs, willows, elders, dogwoods, viburnums, hawthorns, wild crabs, perennials and many others, most of which are native to Iowa, and most of which were raised in a nursery previously established on the Water Supply Lands. The shores were also planted with various species of aquatic plants and the surface of the lagoon was dotted with planting of water lilies and lotus. It was then liberally stocked by the State Fish and Game Association with bass, pike, croppies, perch and blue gills. The supply, for maintaining a constant water level, comes from the waste water of the Plant. It passes through the oil coolers to a fountain, thence to the lagoon overflowing through a sewer into the river. This waste enters the lagoon, from the fountain, over an artificially constructed waterfall.

The fountain, before mentioned, was the development of another borrow pit, smaller in size, about 100 feet by 140 feet,